L3280 LOW VOLTAGE TELEPHONE SPEECH CIRCUIT .. . . . ADVANCE DAT A OPERATION DOWN TO 1.3 V/5 mA DTMF & BEEP TONE INPUTS EXTERNAL MUTING FOR EARPHONE AND MICROPHONE MUTE TURNS ON BEEP TONE & DTMF INPUTS AND TURNS OFF EARPHONE & MICROPHONE SUITABLE FOR DYNAMIC OR PIEZO EARPHONES AND PIEZO, DYNAMIC OR ELECTRET MICROPHONES DESCRIPTION The L3280is a brand new low voltage speech circuit designed to replace hybrid circuits in telephonesets. It is designed for sets that may be operated in parallel. It features both DTMF input and Beep tone input ; ALC on send and receive and muting input. Various DC - characteristics can be programmed at pin 14 replacing testing resistor (43Ω) with proper network value. DIP14 ORDERING NUMBER : L3280AB PIN CONNECTION (top view) June 1993 This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice. 1/8 L3280 BLOCK DIAGRAM ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit VL Line Voltage (3 ms pulse) 20 V IL Line Current 150 mA Ptot Total Power Dissipation, Tamb = 70 °C 1 W Top Operating Temperature – 20 to 55 °C Tj Junction Temperature – 65 to 150 °C Value Unit 80 °C/W THERMAL DATA Symbol Rth j-amb 2/8 Parameter Thermal Resistance Junction-ambient Max L3280 Figure 1 : Test Circuits. Figure 2 . Receiving gain GR = VRO VRI Figure 3. Sending gain and sidetone : GS = VSO ; ST = VRO VMI VMI 3/8 L3280 ELECTRICAL CHARACTERISTICS (Tamb = 25oC ; f = 1kHz ; IL = 20mA : mute low ; R1 (pin 14) = 43Ω, unless otherwise specified) Symbol Parameter Test Conditions Min. Typ. Max. Unit VL Line Voltage IL = 20 mA 3.05 3.35 V VL Line Voltage IL = 50 mA 5.8 6.2 V VL Line Voltage IL = 80 mA 8.5 10 V CMRR Common Mode Rej. Ratio 50 dB GS Sending Gain VMI = 2 mV, IL = 20 mA 47.8 49.3 50.8 dB DGS Delta Sending Gain IL = 70 mA, VMI = 2 mV –7 – 5.5 –4 dB THDS Sending Distortion VSO = 700 mV 5 % N TX Sending Noise IL = 50 mA, VMI = 0 V ZMI Mic. Input Impedance VMI = 2 mV 40 GR Receiving Gain IL = 20 mA, VRI = 0.2 V 7.7 9.2 10.7 dB D GR Delta Receiving Gain IL = 70 mA, VRI = 0.2 V –7 – 5.5 –4 dB THDR Receiving Distortion VRO = 615 mV 5 % NRX Receiving Noise VRI = 0 V 300 µV ZRO Receiving Output Imped. R1 = 200 Ω, VRO = 50 mV 10 Ω Sidetone VMI = 2 mV 40 dB ZML Line Match. Impedance VRI = 0.2 V VL Line Voltage IL = 5.5 mA VSO Sending Output Voltage IL = 5.5 mA, THD = 5 % 100 mV IRO Rec. Output Current IL = 5.5 mA, THD = 5 % 0.7 mA – 71 500 dBm KΩ 600 700 Ω 1.5 1.8 V OPERATION @ IL = 16 mA MULO Mute Input Low (speaking mode) MUHI Mute Input High (dialling mode) 2 GMF DTMF Gain Vin = 2 mV ; Mute = 2 V 25 26.5 RMF DTMF Input Impedance Mute = 2 V 6 8.5 DTMF Distorsion Mute = 2 V ; Vin = 25 mV Gbeep Beeptone Gain Mute = 2 V ; Vin = 25 mV R beep Beeptone Input Imped. Mute = 2 V THD Beeptone Distorsion Mute = 2 V ; VBt = 100 mV DVL DELTA VLINE Mute = 2 V ; IL = 20 mA THDMF GBACK 4/8 Back Tone Gain 1 V 28 dB KΩ 5 8.5 % dB 12 KΩ 0.5 – V – 5 % 1.2 V –3.0 dB L3280 CHARACTERISTIC AT 1 KHZ Figure 4 : Receive Characteristic and Max Output at 2 % THD. Figure 5 : Sending ALC Characteristic and Max Output at 2 % THD. Figure 6 : DC Characteristic Measured between Line and GND. LOGIC OF MUTE SWITCHING DTMF BEEP MIC INPUT RECEIVE INPUT MUTE H ACTIVE TO LINE OUTPUT ACTIVE TO EARPHONE OUTPUT MUTED MUTED MUTE L MUTED MUTED ACTIVE ACTIVE 5/8 L3280 Figure 7 : Application Circuit for Dynamic Transducer. 6/8 L3280 DIP14 PACKAGE MECHANICAL DATA mm a1 0.51 B 1.39 Typ. Max. Min. Typ. Max. 0.020 1.65 0.055 0.065 b 0.5 0.020 b1 0.25 0.010 D 20 0.787 E 8.5 0.335 e 2.54 0.100 e3 15.24 0.600 DIP14.TBL Min. inch F 7.1 0.280 i 5.1 0.201 L Z 3.3 1.27 0.130 2.54 0.050 0.100 PM-DIP14.EPS DIM 7/8 L3280 Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics. 1994 SGS-THOMSON Microelectronics - All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thaliand - United Kingdom - U.S.A. 8/8